"No master pages applied because ..."

[Nancy Allison]

We are using unstructured Framemaker 10 in a Windows 7 environment.

My coworker is getting the error message:

"No master pages applied because the MasterPageMaps table contains no mappaing information.
Book Error Report
C:\ ...\Blah.book"

I googled this error message and the two discussions I've found concern structured FrameMaker, which we're not using.

The error message gives the path to the book file. Does this indicate that the problem resides in the actual *.book file? What am I looking for?

All suggestions gratefully received.

--Nancy